In TSM, the binary tree requires thresholds to be specified to generate child nodes. In our experiments, we choose median values as thresholds. However, it is easy to observe that \(s_b\)  in all experiments are from the lower range (i.e. the left child node). If the thresholds are adaptive and can be updated by the rewards referring to the percentile in TPE [1]}, TSM may be further improved to better focus on adaptively adjusted subspace.
